[Effect of physical training on the metabolic response of the isolated working heart during hypoxia (author's transl)].
The increased tolerance to O2 deprivation of the myocardium after physical training was studied using the isolated working heart preparation and rats moderately trained by swimming. Glycolytic utilization of exogenous glucose and lactate production were determined under oxygenated conditions (Po2 # 500 Torr, 10 min), during severe hypoxia (P02 less than 50 Torr, 10 min) and during post-hypoxic perfusion (Po2 # 500 Torr, 15 min). The energetic state (CP, ATP, ADP, AMP) and glycogen store were determined at the end of the experimental procedure. The beneficial effect of training was evidenced by the restoration of aortic flow in the post-hypoxic period in hearts from trained animals (CE), whereas it did not return to the prehypoxic level in hearts from sedentary animals (CS). The increase in glycolytic utilization of exogenous glucose during hypoxia (x 2.5) was not very different in CE and CS, whereas lactate production was higher (+ 50%) and of longer duration in CE than in CS, This higher lactate production was the consequence of the larger glycogen store in CE than in CS. Moreover, glycogen resynthesis during the post-hypoxic period was higher in CE than in CS. Thus, a changed glycogen metabolism, and also higher CP and ATP contents in CE compared to CS, are examples of metabolic events implicated in the increased tolerance to O2 deprivation of the myocardium induced by physical training.
D000818:Animals; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology*; D010806:Physical Education and Training; D051381:Rats; D011919:Rats, Inbred Strains; D001616:beta-Galactosidase / Q000378:metabolism
D001616:beta-Galactosidase; D005947:Glucose; D010100:Oxygen
Effet de l'entraînement physique sur la réponse métabolique à l'hypoxie du coeur isolé de rat.